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THE SEAWEEDS 
Dipterosiphonia prorepens (A g.) Falkenberg. 
= Polysiphonia prorepens J. Agardh. 
Frond filiform, dwarf, 5 cm. or more long, the primary filaments pros- 
trate, subdistichous, pinnate, secondary ones rising almost vertically, 
secund, alternate. Pinnae regular, pinnellae simple, subulate, obtuse, 
alternate, articulate, six to eight siphons. Tetrasporangia unevenly scat- 
tered on the pinnellae. 
Western Australia (King George Sound), South Africa. 
HERPOSIPHONIA Naegeli. 
Fronds rooting, apices shield-shaped, ecorticate, ascending from a 
horizontal surculus or rarely all erect, laterally branched, terete, complanate 
or two-edged and compressed. Long and short segments distinct; longer 
with dorsiventral structure, apices involute, emitting lateral, distichous, 
alternate, elongate branches; shorter uni- or bi-seriate, giving off long 
segments from dorsal region, radial or dorsiventral structure, apices penicil- 
late but deciduous. Pericentral siphons numerous, 12 to 18. Tetra- 
sporangia evolved in median region of ramuli, in a single series more or less 
irregularly interrupted or regularly disposed. Cystocarps ovate or globose, 
carpospores acrogenous, clavate. Antheridia on apices of ramuli, borne on 
monosiphonous pedicels. 
H erposiphonia rostrata (Sond.J Falkenberg. 
Fronds rising, from prostrate surculi, 2 cm. to 7 cm. long, attached to 
other algae by small adhesive discs. Fronds 2 cm. to 5 cm. high, capillary, 
sub-simple, linear or lanceolate in outline, set throughout with short, simple, 
erecto-patent, falcato-incurved, alternate branches, each subtended by 
several scattered, subsecund or spirally inserted, simple, filiform ramuli. 
Branches pectinated along their lower (outer) side with similar secund 
simple ramuli, one from nearly every node. Articulations as long as broad 
in all parts, those of main stem having 12 to 16 tubes, fewer in the ramuli. 
Cystocarps ovate, terminating a shortened ramulus. Tetmspores lodged 
towards the base of the ramulus, the fertile portion tipped with a beak-like 
barren point. Colour dark purplish-red. 
South Australia (Investigator Strait, Eastern Bays), Western Australia. 
II erposiphonia pectinella (Harv.) Falkenberg. 
= Polysiphonia pectinella Harvey. 
Frond dwarf, arachnoid with prostrate filaments springing from the base, 
irregularly branched ; ramelli shorter and pectinate, slightly curved at the 
apices, vertical, secund, slender, glabrous ; articulate, about eight siphons. 
Colour when dry reddish-purple. Adheres to paper. 
West Australia (King George Sound). 
